Variable frequency compensation for sampled data control systems

Claim 2

In a sampled data feedback system for supplying discontinuous control signals CM according to command signal RM to a plant having an output variable ON and a dominant pole with a characteristic frequency l that reflects said variable ON''s responsiveness to said control signal CM and where said system further includes a summer for summing said command RM and a feedback signal related to said variable ON, thereby producing an error signal ei, and where said system further includes a sampler comprising a compensator and a first sensing means, said compensator periodically sampling said error ei to produce sampled error signal e1* and compensating said error ei*, thereby producing a discontinuous output signal e0*, and said first sensing means for controlling the frequency f at which said compensator compensates said signal ei*, said system also having second means including a hold unit receiving said signal e0* and producing said control CM coupled to said plant, the improvement which resides in compensation for varying said frequency f, said compensating comprising a. third means ascertaining said characteristic frequency l and providing an output signal that is a function of l and b. fourth means coupled to said first sensing means and receiving said output signal of said third means and activating said first sensing means so that compensation frequency f is proportional to said characteristic frequency l.

Claim 3

The improvement as defined in claim 1 wherein said characteristic frequency l is related to parameters of said plate and wherein said third means monitors said parameters and supplies said output signal that is a function of l.

Claim 4

The improvement as defined in claim 1 wherein said characteristic frequency l is related to parameters of said plant''s environment and wherein said third means monitors said parameters and supplies said output signal that is a function of l.

Claim 5

The improvement as defined in claim 1 wherein said characteristic frequency l is related to parameters of said plant and said plant''s environment and wherein said third means monitors said parameters and supplies said output signal that is a function of l.

Claim 6

The improvement as defined in claim 1 wherein said compensator constitutes a digital computer that produces an updated value e0*(t) of said output e0* according to computations based on a difference equation and wherein said first means instructs said computer to repeat said computations at said frequency f.

Claim 7

An improvement in compensation for a sampled data feedback control system supplying a discontinuous control signal CM according to a command signal RM to a plant having an output variable ON and a dominant pole with a characteristic frequency l reflecting said variable ON''s response to said control signal CM and where said system further includes a summer for summing said command RM and a feedback signal related to said variable ON thereby producing an error signal ei, and where said system further includes a sampler comprising a digital computer and a first sensing means, said digital computer periodically sampling said error ei to produce a sampled error signal ei* and compensating said sampled error ei*, thereby producing a compensated discontinuous output signal e0* according to the transfer function where v+v w, by performing the computations based on the difference equation and said first sensing means controlling the frequency f at which said computations are performed, said system further having second means including a hold unit receiving said signal e0* and producing said control signal CM coupled to said plant, said improvement comprising; a. third means for ascertaining said characteristic frequency l and providing an output signal that is a function of l; and b. fourth means coupled to said first sensing means and receiving said output signal of said third means and activating said first sensing means so that compensation frequency f is proportional to characteristic frequency l.

Claim 8

An improvement in compensation for a sampled data feedback control system supplying a discontinuous control signal CM according to a command signal RM to a plant having an output variable ON and a dominant pole with a characteristic frequency l reflecting said variable ON''s response to said control signal CM and where said system further includes a summer for summing said command RM and a feedback signal related to said variable ON thereby producing an error signal ei, and where said system further includes a sampler comprising a digital computer and a first sensing means, said digital computer periodically sampling said error ei to produce a sampled error signal ei* and compensating said sampled error ei*, thereby producing a compensated discontinuous output signal e0* according to the transfer function where v+v w, by performing the computations based on the difference equation and said first sensing means controlling the frequency f at which said computations are performed, said system further having second means including a hold unit receiving said signal e0* and producing said control signal CM coupled to said plant, said improvement comprising; a. third means for ascertaining said characteristic frequency l and providing an output signal that is a function of l; and b. fourth means coupled to said first sensing means and receiving said output signal of said third means and activating said first sensing means so that compensation frequency f is proportional to characteristic frequency l.

Claim 9

The improvement as defined in claim 6 wherein said first means constitutes a sense line coupled to said computer and said fourth means supplies a series of timing pulses each of which causes said sense line to instruct said computer to perform a new computation said pulses having a frequency proportional to said characteristic frequency l.

Claim 10

In a sampled data feedback system for supplying discontinuous control signal CM according to a command signal RM to a plant having an output variable ON and a dominant pole with a characteristic frequency l that reflects said variable ON''s responsiveness to said control signal CM and where said system further includes a summer for summing said command RM and a feedback signal ON'' related to said variable ON thereby producing an error signal ei said system including a feedback sampler, said sampler comprising a compensator that samples and compensates said variable ON to produce said feedback signal ON'' and a first means for controlling the frequency at which said compensator compensates said signal ON, said system further including second means for sampling said error ei producing sampled error signal ei* and third means including a hold unit receiving said sampled error ei* and producing said control signal CM and coupling said signal CM to said plant, the improvement in compensation comprising, a. fourth means ascertaining said characteristic frequency l and providing an output signal that is a function of l, and b. fifth means coupled to said first and second means and receiving said output signal of said fourth means and activating said first and second means so that said compensation of signal ON and said sampling of error ei are synchronized and occur at a frequency fproportional to said characteristic frequency l.

Claim 11

In a sampled data feedback system for supplying discontinuous control signal CM according to a command signal RM to a plant having an output variable ON and a dominant pole with a characteristic frequency l that reflects said variable ON''s responsiveness to said control signal CM and where said system further includes a summer for summing said command RM and a feedback signal ON'' related to said variable ON thereby producing an error signal ei said system including a feedback sampler, said sampler comprising a compensator that samples and compensates said variable ON to produce said feedback signal ON'' and a first means for controlling the frequency at which said compensator compensates said signal ON, said system further including second means for sampling said error ei producing sampled error signal ei* and third means including a hold unit receiving said sampled error ei* and producing said control signal CM and coupling said signal CM to said plant, the improvement in compensation comprising, a. fourth means ascertaining said characteristic frequency l and providing an output signal that is a function of l, and b. fifth means coupled to said first and second means and receiving said output signal of said fourth means and activating said first and second means so that said compensation of signal ON and said sampling of error ei are synchronized and occur at a frequency fproportional to said characteristic frequency l.

Claim 12

The improvement as outlined in claim 8 wherein said compensator constitutes a digital computer that produces an updated value ON''(t) of said feedback signal ON according to computations based on a difference equation and wherein said first means instructs said computer to repeat said computations at said frequency f.

Claim 13

The improvement as set forth in claim 9 wherein said third means includes a digital computer compensating said sampled error ei* according to computations based on a difference equation and activated by said fifth means so that said computations are synchronized with those occurring in said compensator.